Heat pump for KfW55 house 148 sqm

For KfW55, no ventilation system is required. You can quote whatever you want now ;)
My brother-in-law is currently building a KfW55 single-family house without an automatic ventilation system...

We are also building without a ventilation system.
However, in all the calculations, window rebate vents were still taken into account, which somehow got lost during the construction and selection process ;)

Response from the Daikin customer service:

The Daikin outdoor unit ERLA11DAW1 planned for us with 11kW modulates down to 30% of the power, that is 3.3 kW.

This is probably still above the power we need most of the time.

Answer from Daikin customer service:

The Daikin outdoor unit ERLA11DAW1 with 11kW that we have planned modulates down to 30% of the capacity, so down to 3.3 kW.

That is probably still above the power we need most of the time.

At least. But yes, probably 80-90% less will be needed.

What does the setup look like otherwise?

Buffer tank? How large? Mixing valve? Bypass valve? Circulation? ERR?

I can tell you once it is installed. The companies are completely stonewalling, both BT and HB.

ERR yes
Circulation yes (meaning hot water, so that it gets hot faster from the tap? At least something like that seems to be prepared)

To my repeated inquiries to BT, asking them to check whether the 11kW could be plausible, I only got
"The program calculated it that way"
"He has been doing this for 10 years, he is a master of his craft."
Promised answers then do not come.

You probably won't be able to do much there either. You can hope that it won't be too bad and then optimize as best as possible yourself. If it doesn't get completely messed up, you can still achieve quite a bit through adjustments and settings, etc. The last 10% just won't be possible anymore.

There probably isn’t much you can do about it. You can hope that it won’t be too bad and then optimize it yourself as best as possible afterwards. If it’s not completely messed up, you can still achieve quite a bit through adjusting settings, etc. The last 10% just won’t be possible then.

That’s how it will be. When our monster arrives, there will be the optimization thread.